This application is related to Japanese application No. 10(1998)-249265 filed on Sep. 3, 1998, whose priority is claimed under 35 USC xc2xa7119, the disclosure of which is incorporated by reference in its entirety.
1. Field of the Invention
The present invention relates to an anticoagulant and a hemanalysis method, more particularly to an anticoagulant using an antiplatelet agent cocktail and a hemanalysis method using such an anticoagulant.
2. Description of Related Art
Currently, in blood test, an appropriate anticoagulant is selected for use among a variety of anticoagulants depending upon the purpose and type of tests. For example, EDTA salts are often used for blood cell count tests, and citrates are generally used for blood coagulation tests. For biochemical tests, anticoagulants are not used or heparin is used.
Such selection of anticoagulants for use is necessary because determination of test items may be affected by use of an anticoagulant. For example, if an EDTA salt is used for a coagulation test, coagulation time cannot be determined or may be prolonged. On the other hand, use of a citrate for a blood cell count test results in a decrease in the number of platelets because platelets aggregate, and therefore the number of leukocytes increases seemingly. Thus, unless a proper anticoagulant is selected and used depending upon the purpose and type of tests, correct results cannot be obtained from the test, which can lead to a misdiagnosis.
Further, it is known that, even if an EDTA salt is used, agglutination of platelets occurs in some particular samples and thereby a pseudo decrease of platelets takes place. The pseudo decrease means a seeming decrease in the number of platelets. Thus the EDTA salts are not always free from problems in blood cell count tests.
Usually, when blood is analyzed, blood sample of a patient is often taken at once and put in a number of test tubes for blood sampling (about 2 ml to about 5 ml per tube) which contain different anticoagulants. However, this means that a relatively large amount of blood and accordingly much effort are required. Therefore, a burden is imposed on the patient whose blood sample is being taken.
Also the need to prepare test tubes containing different anticoagulants for individual test items raises costs of hemanalysis. Furthermore, an increase in the number of test tubes may enlarge the possibility that test tubes containing blood samples are mistaken for each other.
Accordingly, there is a demand for an anticoagulant which allows a plurality of blood tests to be conducted with one test tube.
The inventors of the present invention have been made an earnest study on anticoagulants for the purpose of providing a simple hemanalysis method and reducing burdens on patients, in other words, for the purpose of providing an anticoagulant and a hemanalysis method which allow both blood cell count tests and coagulation tests or both blood cell count tests and biochemical tests to be carried out on the same blood sample. The inventors of the present invention have tried diverting a so-called CTAD (containing antiplatelet agents of theophylline, adenosine and dipyrldamole as well as citric acid or alkali metal salt thereof and generally used as an anticoagulant for determining activation of platelets, for monitoring a heparin therapy and the like) to leukocyte and erythrocyte counting, which is a quite different use from what the CTAD is conventionally used for. Unexpectedly, it has been found that the leukocyte and erythrocyte counting can be done without adverse effects which were usually expected to be caused by use of the CTAD. Further, it has been found that both blood cell count tests and coagulation tests can be performed with use of the CTAD. Thus the present invention has been achieved.
Also, the inventors have found that both blood cell count tests and biochemical tests can be performed with use of a thrombin inhibitor together with the above-mentioned antiplatelet agents, finally to achieve the present invention.
The present invention provides an anticoagulant for blood cell counting comprising at least two kinds of antiplatelet agents selected from the group consisting of three kinds of antiplatelet agents which are theophyllines (T), adenosines (A) and dipyridamoles (D), and citric acid, an alkali metal salt thereof or a combination of citric acid and an alkali metal salt thereof (C) (also referred to as a citric acid-base anticoagulant hereinafter).
In another aspect, the present invention provides a hemanalysis method comprising adding the above-described anticoagulant for blood cell counting to a blood sample and counting at least two kinds of blood cells selected from the group consisting of leukocytes, erythrocytes and platelets in the blood sample.
In still another aspect, the present invention provides an anticoagulant for blood cell counting comprising at least two kinds of antiplatelet agents selected from the group consisting of three kinds of antiplatelet agents which are theophyllines, adenosines and dipyridamoles, and a thrombin inhibitor.
Further, the present invention provides a hemanalysis method comprising adding this anti-coagulant for blood cell counting to a blood sample and counting at least two kinds of blood cells selected from the group consisting of leukocytes, erythrocytes and platelets in the blood sample.
These and other objects of the present application will become more readily apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.